The present disclosure relates to a battery assembly which has at least one first cell unit of a first cell type and at least one second cell unit of a second cell type, which second cell unit is different from the first cell unit.
Electrical energy stores are used in hybrid, plug-in hybrid and electric vehicles in order to store the energy required for operating the electric motor of the electric vehicle, which electric motor at least partially assists driving of said electric vehicle. So-called lithium-ion batteries are used for this purpose in latest-generation vehicles. The electric vehicle iMiev which comprises lithium-ion batteries of this kind was introduced to the German market in 2011.
Lithium-ion battery cells and lithium-ion batteries are distinguished, amongst other things, by a high energy density and an extremely low level of self-discharging. Said lithium-ion battery cells have at least a positive and a negative electrode, said electrodes also being called cathode and, respectively, anode and being able to reversibly insert lithium ions (Li+) during so-called intercalation or extract said lithium ions again during so-called deintercalation. Drive batteries in hybrid, plug-in hybrid and electric vehicles are usually of modular configuration. In this case, battery modules are formed from at least two battery cells which are interconnected in series or in parallel, said battery modules in turn being combined to form relatively large subunits which can share, for example, a common cooling device. Two or more subunits of this kind can then be interconnected to form a battery, wherein the subunits can also be arranged in several levels one above the other depending on the installation space available.
In practice, high-energy cells are sometimes combined with double-layer capacitors in one energy store, said double-layer capacitors being arranged in two different, separate assemblies. In this case, the double-layer capacitors function as high-power cells which are able to briefly provide high powers. If the combination of high-power cells and high-energy cells is installed, for example, in an electric vehicle, the high-power cells serve, for example in the event of an acceleration operation of the electric vehicle, to provide the high power which is required for said acceleration operation, while the high-energy cells serve to store the energy which is required for traveling over a predetermined range of the electric vehicle. However, the interconnection of high-energy cells and high-power cells within the energy store is relatively complex, in particular since cell units comprising two different assemblies have to be linked to one another.